The overall objective of this project is to evaluate the effects of processing and storage on nutrients in breast milk in the interest of infant nutrition. The final goal is to establish optimal processing conditions which would result in the least deleterious effects and maximal storage stability. A considerable amount of work has been completed relative to the effects of slow freezing, quick freezing and freeze dehydration and storage upon certin B vitamins (niacin, biotin and pantothenic acid), enzymes such as protease, lysozyme, lipase and lactoperoxidase, and several lipid fractions. Some of these studies are in progress. In addition, we propose to look at the effect of heat processing (pasteurization) on the enzymes, B-vitamins, and lipids in breast milk. Preliminary trials concerning the determination of the effect of heat processing upon various nutrients in breast milk have been completed. In these experiments, microbiological studies will be conducted as well since reduction of microbial load and destruction of pathogenic microorganisms are the goals of pasteurization. Also, arrangements are being made to collect colostrum and transitional milk samples so that the nutritional aspects of colostrum, transitional, and mature human milks subjected to heat treatment can be compared. Studies will be conducted to determine the effects of multiple processing, that is, heating followed by freezing and storage, on milk nurients and enzymes. Also, if time permits, the effect of heat processing upon the individual protein fractions, particularly immunoglobulins and lactoferrin, will be examined.